DP12266 Police Patrols and Crime
An influential literature has used the aftermath of terrorist attacks to estimate large effects of police street deployment on crime. However, the elasticities obtained in these settings may not easily extrapolate to more standard circumstances. This paper exploits a natural experiment that aimed to increase police presence in more than 6,000 well-defined areas, by economically-realistic amounts and under relatively normal circumstances. Using data transmitted by GPS devices worn by police officers, we first document exogenous and discontinuous changes in patrolling intensity. We then find that the relation between crime and police patrolling is not statistically different from zero, and that the standard errors are small enough to reject relatively small elasticities. We discuss and empirically evaluate explanations for the apparent lack of deterrence.